1. Field of the Invention
This invention relates to pour spouts for containers of fluid, and more particularly to pour spouts which permit transfers of fluid under the influence of gravity into a receiving vessel without the risk of spillage or overflow.
2. Background Art
The instances are numerous in which a receiving vessel or tank must be filled with a fluid and the environment in which this is accomplished or the nature of the fluid itself demands that spillage be minimized or totally eliminated.
A common example involves the widespread use of internal combustion engines in lawnmowers, chain saws, tractors, motorized recreational vehicles, outboard motors, and other gasoline-powered machinery employed on farms and construction sites. It is undesirable that in filling the fuel reservoirs for such devices gasoline in any appreciable quantity should be spilled. Uncontained gasoline presents health and safety risks to persons nearby, as well as a source of environmental pollution generally. Associated with other fluids, such as cooking or machine oils, pesticides, fertilizers, cleaning fluids, sealants, and even food substances are similar concerns for minimizing spills when fluids are transferred from one container to another.
In such fluid transfers, the opportunity for spills have several causes. First, where the opening into the receiving vessel is narrow, it is often the case that a stream of fluid directed thereinto will, either due to its size or the unsteady hand of the pourer, stray outside of that opening. Where no facilitating pour spout or funnel is employed and the exit of the container of fluid never actually enters the opening to the receiving vessel, this problem is a continuing one throughout the entire pouring process.
Second, containers of fluid, whether or not equipped with facilitating pour spouts or used with funnels, must be tilted toward the receiving vessel in order to initiate a flow of fluid. When this tilting must occur prior to entry of the pour spout into the neck of the receiving vessel or the top of the funnel, spillage is common.
In addition, many spills occur when the receiving vessel to which fluid is being transferred fills and overflows before pouring can be terminated. Such a situation is extremely common in receiving vessels having narrow-necked openings. In such structures, it is difficult for the pourer to visually verify the level of fluid in the receiving container as pouring is occurring. Also, once fluid in the receiving vessel reaches the level of the intake neck of the receiving vessel, additional incoming fluid, rather than being received in the volume of the entire receiving vessel, fills into only in the intake neck thereof. This results in an abrupt increase in the rate of rise in the level of fluid, enhancing the likelihood of an overflow.
A final source of difficulty in controlling transferred fluids to prevent waste and spilling is that frequently the container from which the fluid is being poured is not effectively vented during the pouring process. This can result in an uneven flow of fluid, and even surges of flow which render impossible a reliable prediction of the level of the fluid in the receiving vessel. Surges of fluid flow can also cause splashing. If occurring when the receiving vessel is almost full such surges will certainly cause overflows. In addition, the turbulence created by such surges of flow in the container from which fluid is being poured can shift the weight of that container making it difficult to hold steady.
A further problem related to ineffective venting during pouring is the development of an airlock wherein a total absence of venting in combination with specific volume and viscosity parameters can result in a fluid which will not pour once its container is inverted. On occasion the air lock can be dissipated by righting the container, but such activity causes splashing of the fluid in its container, and the necessity to reenter the pour spout into the receiving vessel thereafter only increase the opportunities for spills.
While a funnel or a narrow-necked pour spout on a fluid container can to a degree reduce spills, such devices without more do not adequately eliminate spills arising due to all of the causes described above. This is particularly true in relation to overflow control in the type of fluid transfers in which fluid flows from a container into a receiving vessel under the influence of gravity exclusively, rather than under circumstances in which pumping motivates motion in the transferred fluid.
The overflow control mechanisms commonly used in service stations for controlling overflow in filling the gas tank of a vehicle are of this latter type. They derive their effectiveness from the fact that the fluid transferred is being moved due to pressure, rather than gravity. By contrast, only gravity is used, for example, to induce the flow of kerosene when that fuel is transferred from a storage container at a campsite into a lantern or a cookstove. It is to such gravity-induced types of fluid transfers that the present invention pertains, and it has been found that prior to this invention, no known satisfactory configuration for a pour spout had been achieved which could consistently facilitate spill-free, clean fluid transfers.